Note: Do not install an on/off switch on the main (red) battery line, or connect the white ignition sense wire to the red battery wire. Both configurations bypass the MP modem's controlled shutdown sequence, and may cause data loss and subsequent
Rev 1.4 Draft Mar.08
Hardware and Software Installation
Ignition sense on/off wiring
This section only applies to installing an MP modem in a vehicle. If you are installing the MP modem in an office building, use the AC/DC adapter.
The MP modem’s power on/off is controlled by the ignition sense line (white wire) using internal software, rather than a hard on/off switch on the red power line. The red, black, and white wires connect to the battery and ignition switch as shown in the power harness wiring diagram.
Note: The battery cable used for a car, truck, or other mobile connection must be less than 3 meters in length.
Switch (vehicle | Red wire | 5 A fuses (on red |
ignition key, or | (Battery) | and white only) |
separate) |
| MP modem |
|
|
White wire | Black unfused wire |
(Ignition sense) | (Ground) |
Vehicle battery
Figure
•When the white ignition sense line is pulled high (5 to 36 V), the MP modem powers on.
•When the ignition sense line is pulled low (less than 2 V), the MP modem performs a controlled shutdown sequence (under software control), de‐registering and saving any relevant operational data before powering off.
Ignition sense options
There are three ways to connect the ignition sense wiring:
•Engine on only. Connect the white ignition sense wire to the vehicle’s ignition switch so that the MP modem is powered on only when the ignition key is switched to the full “On” position, that is, when the engine has been started. In this configuration, the engine must be running for the MP modem to be on.
•Accessory on. Connect the white ignition sense wire to the vehicle’s ignition switch so that the MP modem is powered
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